# 输入 - input()函数
# s = input("请输入一句话：")
# # 输出 - print()函数
# print(s) 
# print(type(s))   

# s = input("输入年龄：")
# # int() - str->int
# age = int(s)
# print(age,type(age))

# age+=1
# print(age)  
# s+='1'
# print(s)   

s=input("请输入圆周率：")
# float()   str->float
pi = float(s)
print(pi,type(pi))   

# float->int
a=int(pi)
print(a,type(a)) 

# int - float
b = float(a)
print(b,type(b))   

# ->str
s2 = str(pi)
print(s2,type(s2))   

